Central resource involvement during the visual search for single features and conjunctions of features

Abstract

The present experiment investigated the attentional demands of visual search for targets defined by a single feature (feature search), or a conjunction of separable features (conjunctive search). The visual search task was based on Treisman and Gelade's (1980) visual search paradigm, which typically reveals a large interaction between search condition and display size. The present experiment differed from theirs, however, by the inclusion of a concurrent task, which was a simple detection response to an auditory probe. This concurrent task measured the involvement of central processing resources during feature and conjunctive search, from the moment the array was presented until initiating a visual search response. Marked interference effects during the first 50 msec of array presentation demonstrated the involvement of central processing resources in the two visual search conditions. Further, the data is suggestive of the notion that both feature registration and feature combination compete for our limited attentional resources.